if_lua.txt For Vim version 8.1. Last change: 2015 Oct 16
VIM REFERENCE MANUAL by Luis Carvalho
The Lua Interface to Vim luaLua
1. Commands lua-commands
2. The vim module lua-vim
3. List userdata lua-list
4. Dict userdata lua-dict
5. Funcref userdata lua-funcref
6. Buffer userdata lua-buffer
7. Window userdata lua-window
8. The luaeval function lua-luaeval
9. Dynamic loading lua-dynamic{Vi does not have any of these commands}
The Lua interface is available only when Vim was compiled with the
+lua feature.
==============================================================================
1. Commands lua-commands:lua
:[range]lua {chunk}
Execute Lua chunk {chunk}. {not in Vi}
Examples:
:lua print("Hello, Vim!") :lua local curbuf = vim.buffer() curbuf[7] = "line #7"
:[range]lua <<{endmarker}{script}{endmarker}
Execute Luascript{script}. {not in Vi}Note: This command doesn't work when the Lua
feature wasn't compiled in. To avoid errors, see
script-here.{endmarker}must NOT be preceded by any white space. If {endmarker}is
omitted from after the "<<",a dot '.' must be used after {script}, like
for the :append and :insert commands.
This form of the :lua command is mainly useful for including Lua code
in Vim scripts.
Example:
function! CurrentLineInfo() lua << EOF local linenr = vim.window().line local curline = vim.buffer()[linenr] print(string.format("Current line [%d] has %d chars", linenr, #curline)) EOF endfunction
To see what version of Lua you have:
:lua print(_VERSION)
If you use LuaJIT you can also use this:
:lua print(jit.version):luado
:[range]luado {body} Execute Lua function "function (line, linenr) {body}end" for each line in the [range], with the function
argument being set to the text of each line in turn,
without a trailing <EOL>, and the current line number.
If the value returned by the function isastringit
becomes the text of the line in the current turn. The
default for [range]is the whole file: "1,$".{not in Vi}
Examples:
:luado return string.format("%s\t%d", line:reverse(), #line) :lua require"lpeg" :lua -- balanced parenthesis grammar: :lua bp = lpeg.P{ "(" * ((1 - lpeg.S"()") + lpeg.V(1))^0 * ")" } :luado if bp:match(line) then return "-->\t" .. line end:luafile
:[range]luafile {file}
Execute Luascript in {file}. {not in Vi}
The whole argument is used asa single file name.
Examples:
:luafile script.lua :luafile %
All these commands execute aLua chunk from either the command line (:lua and
:luado) or a file (:luafile) with the given line [range]. Similarly to the Lua
interpreter, each chunk has its own scope and so only global variables are
shared between command calls. All Lua default libraries are available. In
addition, Lua "print" function has its output redirected to the Vim message
area, with arguments separated by a white space instead of a tab.
Lua uses the "vim" module (see lua-vim) to issue commands to Vim
and manage buffers(lua-buffer) and windows(lua-window). However,
procedures that alter buffer content, open new buffers, and change cursor
position are restricted when the command is executed in the sandbox.==============================================================================
2. The vim module lua-vimLua interfaces Vim through the "vim" module. The first and last line of the
input range are stored in "vim.firstline" and "vim.lastline" respectively. The
module also includes routines for buffer, window, and current line queries,
Vim evaluation and command execution, and others.
vim.list([arg]) Returns an empty list or, if "arg" isaLua
table with numeric keys 1, ..., n (a
"sequence"), returns alistl such that l[i] =
arg[i] for i= 1, ..., n (see List).
Non-numeric keys are not used to initialize
the list. See also lua-eval for conversion
rules. Example:
:lua t = {math.pi, false, say = 'hi'} :echo luaeval('vim.list(t)') :" [3.141593, v:false], 'say' is ignored
vim.dict([arg]) Returns an empty dictionary or, if "arg" isaLua table, returns adictd such that d[k] =
arg[k] for all string keys k in "arg" (see
Dictionary). Number keys are converted to
strings. Keys that are not strings are not
used to initialize the dictionary. See also
lua-eval for conversion rules. Example:
:lua t = {math.pi, false, say = 'hi'} :echo luaeval('vim.dict(t)') :" {'1': 3.141593, '2': v:false, :" 'say': 'hi'}
vim.funcref({name}) Returns aFuncref to function {name} (see
Funcref). It is equivalent to Vim's
function().
vim.buffer([arg]) If "arg" isa number, returns buffer with
number "arg" in the buffer list or, if "arg"
isa string, returns buffer whose full or short
name is "arg". In both cases, returns 'nil'
(nil value, not string) if the buffer is not
found. Otherwise, if "toboolean(arg)" is'true' returns the first buffer in the buffer
list or else the current buffer.
vim.window([arg]) If "arg" isa number, returns window with
number "arg" or 'nil' (nil value, not string)
if not found. Otherwise, if "toboolean(arg)"
is'true' returns the first window or else the
current window.
vim.type({arg}) Returns the type of {arg}. It is equivalent to
Lua's "type" function, but returns "list",
"dict", "funcref", "buffer", or "window" if
{arg}isa list, dictionary, funcref, buffer,
or window, respectively. Examples:
:lua l = vim.list() :lua print(type(l), vim.type(l)) :" list
vim.command({cmd}) Executes the vim (ex-mode) command {cmd}.
Examples:
:lua vim.command"set tw=60" :lua vim.command"normal ddp"
vim.eval({expr}) Evaluates expression{expr} (see expression),
converts the result to Lua, and returns it.
Vim strings and numbers are directly converted
to Lua strings and numbers respectively. Vim
lists and dictionaries are converted to Lua
userdata (see lua-list and lua-dict).
Examples:
:lua tw = vim.eval"&tw" :lua print(vim.eval"{'a': 'one'}".a)
vim.line() Returns the current line (without the trailing
<EOL>), aLua string.
vim.beep() Beeps.
vim.open({fname}) Opens a new buffer for file {fname} and
returns it. Note that the buffer is not set as
current.
==============================================================================
3. List userdata lua-listList userdata represent vim lists, and the interface tries to follow closely
Vim's syntax for lists. Since lists are objects, changes in list references in
Lua are reflected in Vim and vice-versa. Alist "l" has the following
properties and methods:
Properties
----------o "#l" is the number of items in list "l", equivalent to "len(l)"
in Vim.
o "l[k]" returns the k-th item in "l"; "l" is zero-indexed, as in Vim.
To modify the k-th item, simply do "l[k] = newitem"; in
particular, "l[k] = nil" removes the k-th item from "l".o "l()" returns an iterator for "l".
Methods
-------o "l:add(item)" appends "item" to the end of "l".o "l:insert(item[, pos])" inserts "item" at (optional)
position "pos" in the list. The default value for "pos" is 0.
Examples:
:let l = [1, 'item'] :lua l = vim.eval('l') -- same 'l' :lua l:add(vim.list()) :lua l[0] = math.pi :echo l[0] " 3.141593 :lua l[0] = nil -- remove first item :lua l:insert(true, 1) :lua print(l, #l, l[0], l[1], l[-1]) :lua for item in l() do print(item) end==============================================================================
4. Dict userdata lua-dict
Similarly to list userdata, dict userdata represent vim dictionaries; since
dictionaries are also objects, references are kept between Lua and Vim. Adict
"d" has the following properties:
Properties
----------o "#d" is the number of items in dict "d", equivalent to "len(d)"
in Vim.
o "d.key" or "d['key']" returns the value at entry "key" in "d".
To modify the entry at this key, simply do "d.key = newvalue"; in
particular, "d.key = nil" removes the entry from "d".o "d()" returns an iterator for "d" and is equivalent to "items(d)" in
Vim.
Examples:
:let d = {'n':10} :lua d = vim.eval('d') -- same 'd' :lua print(d, d.n, #d) :let d.self = d :lua for k, v in d() do print(d, k, v) end :lua d.x = math.pi :lua d.self = nil -- remove entry :echo d==============================================================================
5. Funcref userdata lua-funcrefFuncref userdata represent funcref variables in Vim. Funcrefs that were
defined with a "dict" attribute need to be obtained asa dictionary key
in order to have "self" properly assigned to the dictionary (see examples
below.) A funcref "f" has the following properties:
Properties
----------o "#f" is the name of the function referenced by "f"
o "f(...)" calls the function referenced by "f" (with arguments)
Examples:
:function I(x) : return a:x : endfunction :let R = function('I') :lua i1 = vim.funcref('I') :lua i2 = vim.eval('R') :lua print(#i1, #i2) -- both 'I' :lua print(i1, i2, #i2(i1) == #i1(i2)) :function Mylen() dict : return len(self.data) : endfunction :let mydict = {'data': [0, 1, 2, 3]} :lua d = vim.eval('mydict'); d.len = vim.funcref('Mylen') :echo mydict.len() :lua l = d.len -- assign d as 'self' :lua print(l())==============================================================================
6. Buffer userdata lua-buffer
Buffer userdata represent vim buffers. A buffer userdata "b" has the following
properties and methods:
Properties
----------o "b()" sets "b" as the current buffer.
o "#b" is the number of lines in buffer "b".o "b[k]" represents line number k: "b[k] = newline" replaces line k
with string "newline" and "b[k] = nil" deletes line k.
o "b.name" contains the short name of buffer "b" (read-only).
o "b.fname" contains the full name of buffer "b" (read-only).
o "b.number" contains the position of buffer "b" in the buffer list
(read-only).
Methods
-------o "b:insert(newline[, pos])" inserts string "newline" at (optional)
position "pos" in the buffer. The default value for "pos" is
"#b + 1". If "pos ==0" then "newline" becomes the first line in
the buffer.
o "b:next()" returns the buffer next to "b" in the buffer list.
o "b:previous()" returns the buffer previous to "b" in the buffer
list.
o "b:isvalid()" returns 'true' (boolean) if buffer "b" corresponds to
a "real" (not freed from memory) Vim buffer.
Examples:
:lua b = vim.buffer() -- current buffer :lua print(b.name, b.number) :lua b[1] = "first line" :lua b:insert("FIRST!", 0) :lua b[1] = nil -- delete top line :lua for i=1,3 do b:insert(math.random()) end :3,4lua for i=vim.lastline,vim.firstline,-1 do b[i] = nil end :lua vim.open"myfile"() -- open buffer and set it as current function! ListBuffers() lua << EOF local b = vim.buffer(true) -- first buffer in list while b ~= nil do print(b.number, b.name, #b) b = b:next() end vim.beep() EOF endfunction==============================================================================
7. Window userdata lua-window
Window objects represent vim windows. Awindow userdata "w" has the following
properties and methods:
Properties
----------o "w()" sets "w" as the current window.
o "w.buffer" contains the buffer of window "w" (read-only).
o "w.line" represents the cursor line position in window "w".o "w.col" represents the cursor column position in window "w".o "w.width" represents the width of window "w".o "w.height" represents the height of window "w".
Methods
-------o "w:next()" returns the window next to "w".o "w:previous()" returns the window previous to "w".o "w:isvalid()" returns 'true' (boolean) if window "w" corresponds to
a "real" (not freed from memory) Vim window.
Examples:
:lua w = vim.window() -- current window :lua print(w.buffer.name, w.line, w.col) :lua w.width = w.width + math.random(10) :lua w.height = 2 * math.random() * w.height :lua n,w = 0,vim.window(true) while w~=nil do n,w = n + 1,w:next() end :lua print("There are " .. n .. " windows")==============================================================================
8. The luaeval function lua-luaevallua-eval
The (dual) equivalent of "vim.eval" for passing Lua values to Vim is
"luaeval". "luaeval" takes an expressionstring and an optional argument and
returns the result of the expression. It is semantically equivalent in Lua to:
local chunkheader = "local _A = select(1, ...) return " function luaeval (expstr, arg) local chunk = assert(loadstring(chunkheader .. expstr, "luaeval")) return chunk(arg) -- return typval endNote that "_A" receives the argument to "luaeval".Lua numbers, strings, and
list, dict, and funcref userdata are converted to their Vim respective types,
while Lua booleans are converted to numbers. An error is thrown if conversion
of any of the remaining Lua types, including userdata other than lists, dicts,
and funcrefs, is attempted.
Examples:
:echo luaeval('math.pi') :lua a = vim.list():add('newlist') :let a = luaeval('a') :echo a[0] " 'newlist' :function Rand(x,y) " random uniform between x and y : return luaeval('(_A.y-_A.x)*math.random()+_A.x', {'x':a:x,'y':a:y}) : endfunction :echo Rand(1,10)==============================================================================
9. Dynamic loading lua-dynamic
On MS-Windows and Unix the Lua library can be loaded dynamically. The
:version output then includes +lua/dyn.
This means that Vim will search for the Lua DLL or shared library file only
when needed. When you don't use the Lua interface you don't need it, thus
you can use Vim without this file.
MS-Windows
To use the Lua interface the Lua DLL must be in your search path. In a
console window type "path" to see what directories are used. The 'luadll'
option can be also used to specify the Lua DLL. The version of the DLL must
match the Lua version Vim was compiled with.
Unix
The 'luadll' option can be used to specify the Lua shared library file instead
of DYNAMIC_LUA_DLL file what was specified at compile time. The version of
the shared library must match the Lua version Vim was compiled with.
==============================================================================
vim:tw=78:ts=8:noet:ft=help:norl: